Bollards

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Originator: Office of the Chief Technology Officer

Publication_Date: 20091202

Title: Bollards

Edition: 1st Edition

Geospatial_Data_Presentation_Form: vector digital data

Online_Linkage:

Server=10.1.11.144; Service=5151; User=dcgis; Version=SDE.DEFAULT

Larger_Work_Citation:

Citation_Information:

Originator: DC GIS

Title: DC Geographic Information System

Geospatial_Data_Presentation_Form: vector digital data

Description:

Abstract:

Bollards. The dataset contains polygons representing planimetric grates created as part of the DC Geographic Information System (DC GIS) for the D.C. Office of the Chief Technology Officer (OCTO). These features were originally captured in 1999 and updated in 2005 and 2008.
The following planimetric layers were updated using 2008 imagery - Grates (GratePt) - Bollards (BollardPt) - Stairs (StairPly) - Pools (SwmPoolPly). All DC GIS data is stored and exported in Maryland State Plane coordinates NAD 83 meters. METADATA CONTENT IS IN PROCESS OF VALIDATION AND SUBJECT TO CHANGE.

Purpose:

This data is used for the planning and management of Washington, D.C. by local government agencies.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20080528

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: As needed

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -77.112439

East_Bounding_Coordinate: -76.909954

North_Bounding_Coordinate: 38.986212

South_Bounding_Coordinate: 38.812818

Data_Set_G-Polygon:

Data_Set_G-Polygon_Outer_G-Ring:

G-Ring_Point:

Keywords:

Theme:

Theme_Keyword_Thesaurus: none

Theme_Keyword: Grate

Theme_Keyword: Sewer

Place:

Place_Keyword: Washington, D.C.

Place_Keyword: District of Columbia

Place_Keyword: DC

Place_Keyword: DC GIS

Place_Keyword: DCGIS

Use_Constraints:

For data terms and conditions, go to <http://dc.gov/page/terms-and-conditions-use-district-data>

Point_of_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: GIS Data Coordinator

Contact_Organization: DC Office of the Chief Technology Officer (OCTO)

Contact_Address:

Address_Type: mailing and physical address

Address: 801 7th Street SW

City: Washington DC

Postal_Code: 20024

Country: USA

Contact_Voice_Telephone: (202) 727-5660

Contact_Electronic_Mail_Address: [email protected]

Hours_of_Service: 8:30 am - 5:00 pm

Data_Set_Credit: Office of the Chief Technology Officer

Native_Data_Set_Environment:

Microsoft Windows 2000 Version 5.0 (Build 2195) Service Pack 4; ESRI ArcCatalog 9.2.6.1500

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report: Validated by source and/or responsible agency.

Logical_Consistency_Report:

Validated by KCI Technologies, Inc. and OCTO. OCTO developed and operated a QA/QC program to check the deliverables. Generally, the program consists of various types of processes grouped into visual checks, automated procedures, edge-matching routines, and specialized checks.
Staff identified issues in a shapfile with appropriate descriptions for the vendor to fix. The data was delivered in preliminary format for a thorough review and identification of issues. The vendor fixed the data and delivered final data which OCTO checked to ensure the vendor made the fixes appropriately.

Completeness_Report:

Only bollards will be updated. Includes major bollards for public buildings. Small bollards such as those associated with minor shopping plaza and in residential areas will be deleted when they no longer exist but will not be captured if new.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

Horizontal Accuracy of updated 2008 planimetric data is in accordance with ASPRS Class I Accuracy standards for 1"=100' scale mapping.

Vertical_Positional_Accuracy:

Vertical_Positional_Accuracy_Report: N/A

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator: Office of the Chief Technology Officer

Publication_Date: 20080528

Title: Aerial Photography - 2008

Online_Linkage: <http://dcgis.dc.gov>

Type_of_Source_Media: filmstrip

Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 20080525

Source_Currentness_Reference: ground condition

Source_Citation_Abbreviation: aerial photography

Source_Contribution:

New aerial photography was collected in the Spring of 2008 to support new orthoimagery and planimetric updates. This aerial photography was composed of approximately 52 flight lines and a total of 1552. The mission was flown with one Vecxel Ultracam X camera and collected ABGPS and IMU for each exposure.

Process_Step:

Process_Description:

This process describes 2008 updates to planimetric data originally captured in 1999/2005. The CAPTUREYEAR field contains the data of origin for the feature. Aerial Photography
New aerial photography was collected in the Spring of 2008 to support new orthoimagery and planimetric updates. This aerial photography was composed of approximately 52 flight lines and a total of 1552 exposures. The mission was flown with one Vecxel Ultracam X camera and collected ABGPS and IMU for each exposure.
Aerial triangulation
Aerial triangulation is the simultaneous space resection of image rays projected and recorded at one source, the perspective center of the aerial camera. These image rays projected from two or more overlapping images, stereo-models, intersect at the corresponding ground location to determine the three-dimensional coordinates of each point measured. This collection of image rays is fit to known ground survey control in a simultaneous 3-dimensional least squares adjustment. After the completion of this adjustment, coordinates of the 'unknown' ground points are derived by the intersection of the adjusted image points. The purpose of aerial triangulation is to densify horizontal and vertical control from relatively few ground control points (GCPs). Since obtaining GCPs is a relatively significant expense in any mapping project, AT procedures are used to reduce the amount of field survey required by extending control to all stereo-models. This method is essentially a mathematical tool, capable of extending control to areas between ground survey points using several contiguous uncontrolled stereo-models.
SoftCopy Measurements
All photo measurements were directly observed in a digital 'softcopy' environment. Z/I Imaging, an Intergraph - Carl Zeiss joint venture, software and hardware were used to perform the photo measurements.
In order to perform measurements of digital images in softcopy, images must be processed to a panchromatic .tif format using Vexcel Ultacam Office Processing Center (OPC) Version 2.3
Photo Measurements
AT requires that a series of photographs be situated with one another in a continuous strip configuration. The orientation of any photograph that does not contain sufficient number of ground control points is determined by the orientation of the adjacent photographs. In a strip formation, each photograph aids in the exterior orientation of the adjacent photography through the pass points located in the triple overlap areas. This tri-lap area refers to the common ground area shared by two stereo-models (three consecutive photographs) along the strip. As mentioned above, a pass point is an image point that is common to two or more consecutive photographs along that strip. As the pass point is prepared and measured in a stereo-model, it can be used as control to orient the adjacent stereo-model. Thus, the point "passes" control down the strip. A pass point that is common to adjacent strips of photographs is called a tie point. Tie points hold two adjacent strips together similar to a pass point holding or tying together adjacent photos along a strip. The location of the tie and pass points are in areas which allow geometrically stability in strips and the blocks. These locations are known as the Von Gruber points.
The automatic Point measurement feature of the ZI software was used to measure the pass points in this project. This feature automatically records the image coordinates of up to 7 matched points in each Von Gruber area. All ground control points were also manually measured.
Internal software checks were performed to detect gross errors in the photo measurements.
Simultaneous Adjustment by Bundles
The surveyed control, along with the reduced image coordinates, served as input into the 'combined' block adjustment. Three-dimensional, simultaneous least squares adjustments by bundles, commonly referred to as "bundle" adjustments, were undertaken using Intergraph's PhotoT adjustment software. This particular bundle method is very sensitive to systematic errors of the photo measurements and provides the correction of constant and regular errors through self-calibration. This concept regards these types of errors to be common to all photographs or to be present in sub-sets of the photographs. This bundle block adjustment software has proven to be a very rigorous and stable platform. A series of aerial triangulation solutions were completed. The adjustment strategy was devised to provide the optimal solution for the subsequent mapping, while providing comprehensive quality control to detect errors, omissions and spurious data.
Fully Constrained Adjustment
The final adjustment, and the optimal solution to be used for mapping, included all control points as constraints. All image points were assigned standard deviations of 3 m.
Thirty (30) horizontal-vertical control points and one (1) vertical control point were used to constrain the AT solution. All existing ground control points were photo identified. The airborne GPS was weighted at 0.14 meters in all three dimensions. The results may be found in Table 2 of this report.
The sigma naught is a significant indicator of the quality of the adjustment. The sigma value derived by the adjustment is the root mean square of all photo measurement residuals for the entire block. The lower the sigma naught value, the less tension within the adjustment. Typically, a sigma naught in the range of 2 - 4 m is an indication of a high quality internal adjustment. The sigma naught value for the City of Washington block was 1.71 m.
Computation of Final Coordinates and Elevations
After the completion of the final AT solutions, the local space rectangular coordinates of the tie and pass points were transformed back into NAD83 and NAVD88 horizontal coordinates and orthometric heights. The final horizontal coordinates are Maryland (zone 1900) state plane coordinates All final values as presented in the AT report are in the following measurement units:
- Coordinate - X,Y (State Plane Maryland State Plane Coordinates in NAD83/91) in units of meters - Elevation - Z (NAVD 88 U.S. Survey feet) in units of feet
The final AT solution was found to be of a very high quality and will meet or exceed the ASPRS Class I accuracy standards for 1"=100' scale mapping with 2 foot contours.
Digital Elevation Model (DEM):
Previously produced DEM data was available to support the production process. Because no suitable DEM was available for areas outside of the Washington DC city boundary, USGS 10-Meter NED surface was processed and merged with the existing DEM data and used for rectification. Planimetric Data Capture and Edit: All planimetric features were stereocompiled using softcopy photogrammetric workstations. Planimetric features included the following layers:
- Grates - Bollards - Stairs - Swimming Pools

Each layer contained one or more features, each of which was individually coded based on its feature type. Capture actions describe the 2008 edits which were applied to a given feature (U=update, "N"=new, E=Extended). All features were compiled in accordance with industry standards photogrammetric features. The overall process is described below:
- Source materials obtained from the City (imagery, AT, Control) - Stereo-Model boundaries are created for the entire area of interest. - Imagery, AT information and data files for a model boundary are brought into Microstation V7 - Existing DTM data from the City is brought so that it is viewable - Specific planimetric features are newly compiled in a 3D stereo-environment in compliance with the specifications detailed in the database design. A DGN file is the deliverable to the Vector department. ZI-Imaging photogrammetric workstations used for compilation - Planimetric features are exported from DGNs and converted to ESRI shapefiles according to the schema. - Polylines are cleaned and converted into polygons for closed features (structures, roads, parking lots, etc.) - The delivery database is set up and domains are created. The polygons and polylines are appended into the correct feature class in the geodatabase. - The database is QCed visually, and using a database topology reviewer. Any missing features are added and errors are corrected.
Data was delivered to the City. Planimetric data was extensively QC'd by the City and returned to Sanborn for corrections. Corrections were made and comments were added into a correction file for each item addressed. The data then underwent a second City review prior to distribution.

Source_Used_Citation_Abbreviation: C:\OCTOGIS\Data\Metadata\TemplateDCStat

Process_Date: 20090901

Process_Contact:

Contact_Information:

Contact_Person_Primary:

Contact_Person: Shawn Benham

Contact_Organization: Sanborn Map Company

Contact_Position: Project Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 200 I Street SE, 5th Floor

City: Colorado Springs

State_or_Province: Colorado

Postal_Code: 80920

Country: USA

Contact_Voice_Telephone: (719) 502-1296

Contact_Electronic_Mail_Address: [email protected]

Hours_of_Service: <The hours of service of the process point of contact.>

Process_Step:

Process_Description: Metadata imported.

Source_Used_Citation_Abbreviation: C:\temp\GratePt.xml

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: Entity point

Point_and_Vector_Object_Count: 11608

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Planar:

Grid_Coordinate_System:

Grid_Coordinate_System_Name: State Plane Coordinate System

State_Plane_Coordinate_System:

SPCS_Zone_Identifier: 1900

Lambert_Conformal_Conic:

Standard_Parallel: 38.300000

Standard_Parallel: 39.450000

Longitude_of_Central_Meridian: -77.000000

Latitude_of_Projection_Origin: 37.666667

False_Easting: 400000.000000

False_Northing: 0.000000

Planar_Coordinate_Information:

Planar_Coordinate_Encoding_Method: coordinate pair

Coordinate_Representation:

Abscissa_Resolution: 0.000063

Ordinate_Resolution: 0.000063

Planar_Distance_Units: meters

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: North American Vertical Datum of 1988

Altitude_Resolution: 1.000000

Altitude_Distance_Units: feet

Altitude_Encoding_Method:

Explicit elevation coordinate included with horizontal coordinates

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: DCGIS.BollardPt

Attribute:

Attribute_Label: CAPTUREACTION

Attribute_Definition: capture action of feature

Attribute:

Attribute_Label: Shape

Attribute_Definition: Feature geometry

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Attribute:

Attribute_Label: GIS_ID

Attribute_Definition: OCTO GIS sequential identifier

Attribute:

Attribute_Label: FEATURECODE

Attribute_Definition: Feature code

Attribute:

Attribute_Label: DESCRIPTION

Attribute_Definition: Feature code description

Attribute:

Attribute_Label: CAPTUREYEAR

Attribute_Definition: Capture date of feature

Attribute:

Attribute_Label: SHAPE

Attribute_Definition: Feature geometry.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Attribute:

Attribute_Label: OBJECTID

Attribute_Definition: Internal feature number.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are automatically generated.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: DC Office of the Chief Technology Officer

Contact_Person: GIS Data Coordinator

Contact_Address:

Address_Type: mailing and physical address

Address: 200 I Street SE, 5th Floor

City: Washington

State_or_Province: DC

Postal_Code: 20001

Country: USA

Contact_Facsimile_Telephone: (202) 727-5660

Contact_Electronic_Mail_Address: [email protected]

Hours_of_Service: 8:30 am - 5:30 pm

Resource_Description: Downloadable Data

Distribution_Liability:

For data terms and conditions, go to <http://dc.gov/page/terms-and-conditions-use-district-data>

Standard_Order_Process:

Digital_Form:

Digital_Transfer_Information:

Transfer_Size: 0.040

Digital_Transfer_Option:

Online_Option:

Computer_Contact_Information:

Network_Address:

Ordering_Instructions: All data is available at <http://opendata.dc.gov>

Metadata_Reference_Information:

Metadata_Date: 20100517

Metadata_Review_Date: 20091204

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: D.C. Office of the Chief Technology Officer

Contact_Person: GIS Data Coordinator

Contact_Address:

Address_Type: mailing and physical address

Address: 200 I Street SE, 5th Floor

City: Washington

State_or_Province: DC

Postal_Code: 20001

Country: USA

Contact_Facsimile_Telephone: (202) 727-5660

Contact_Electronic_Mail_Address: [email protected]

Hours_of_Service: 8:30 am - 5 pm

Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Time_Convention: local time

Metadata_Extensions:

Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>

Profile_Name: ESRI Metadata Profile